Wireless communication networks, such as wireless wide-area network or wireless local-area networks (WLAN) such as IEEE 802.11 wireless communication networks are able to provide communications for their mobile subscriber units (MSU) utilizing wireless access support through local access points (AP). One task that any MSU typically deals with is an ongoing evaluation of mobile connectivity conditions in the radio frequency (RF) environment in order to make informed decisions to maintain a stable wireless connection with seamless handoffs within the network as the MSU roams through the network. The MSU, for example, can scan for all neighboring APs and evaluate conditions on all available channels to determine good handoff candidates. However, this requires an extensive amount of communications overhead, processing, time, and battery power on the part of the MSU.
For example, the MSU uses critical roaming decisions algorithms to find nearby Basic Service Set Identifiers (BSSIDs) by dwelling its receiver for some significant amount of time on each of the available different channels (pending if passive or active scan or both), to see if more coverage is available. Additionally, this is done without a pre-assessment of the channel occupancy, to know if it is even worthwhile investing that time and power, and even if the coverage is to be found that coverage might have problems with interference, weak signals, etc. If an MSU is lucky, a reasonably strong neighbor BSSID may be found quickly. However, on average, by the time a good BSSID is found more scanning time is spent, and during that time the MSU could be moving, which could weaken the connection with a currently-serving BSSID too much, and the decision to hand-off to next BSSID may be too late, risking the loss or dropping of packets.
A number of WLAN protocols facilitate information exchange between the MSU and APs with regards to RF conditions. For example, Institute of Electrical and Electronics Engineers (IEEE) 802.11k can inform the MSU with Radio Resource Measurements data, which is compiled to reflect RF utilization, load, capacity, noise, interference, central modeling of the network, etc. This data is very helpful for an MSU's scanning and roaming decisions. However, producing this information requires active messaging between the MSU and AP, and is not under the control of the MSU. In addition, this active messaging is not trivial to synchronize, and could be interruptive when there is an active voice or video session over a current WLAN link.
Accordingly, there is a need for a technique for mobile subscriber units to establish mobile connectivity conditions in a network, while eliminating the aforementioned issues. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing background.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.